JPS619903A - Production of steel belt - Google Patents

Abstract

PURPOSE:To form a steel belt having good characteristics and quality without weld defects by subjecting a stock for the welded endless belt which is an annealed maraging steel or precipitation hardening type stainless steel having a specific thickness or below to cold working at a specific reduction ratio and further to an aging treatment. CONSTITUTION:The terminals of the annealed maraging steel or precipitation hardening type stainless steel rolled to <=1mm. thickness are welded to each other to form the steel for endless belt. The steel is cold worked at 20-50% reduction ratio to press-weld the weld zone and to eliminate defects, thereby improving the strength of the weld zone. The steel is further subjected to the hot aging treatment over the entire part to improve further the quality and characteristics thereof. The breaking life of the belt is remarkably increased and the cost of production is considerably reduced as compared to the conventional spinning method, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method of manufacturing a steel belt used as a band saw or a power transmission mechanism component.

(Prior Art) Conventionally, steel belts have been widely used as parts of power transmission mechanisms (for example, CVT belts).
A commonly used steel belt is produced by welding both ends of a cold-rolled thin plate into an endless steel belt.

However, with such conventional steel belts,
Since they often have defects in welded parts and are poor in strength, they cannot be used in areas with strict requirements.

On the other hand, when manufacturing an endless steel belt that requires excellent tensile strength and fatigue strength, a special method is used in which the material vibrator is stretched thinly by spinning processing, etc., and then cut into rings of predetermined dimensions. However, this processing method requires a gripping part for the material pipe, which has the disadvantages of poor product yield and low processing efficiency, and the problem is that it becomes extremely expensive. there were.

(Purpose of the Invention) Therefore, in order to solve the above-mentioned conventional problems, in order to develop an economical and high-performance endless steel belt manufacturing method, the belt material and manufacturing method were improved. After detailed research, we found that by cold working a predetermined amount of steel belt material that has been made into an endless shape by welding, weld defects are crimped, eliminating any negative effects caused by them, and improving the strength of the weld. It has been discovered that by further heat-treating the steel, the properties can be further improved and an endless steel belt with excellent properties can be manufactured.

(Structure of the Invention) That is, the method for manufacturing a steel belt according to the present invention involves welding maraging steel or precipitation hardening stainless steel that has been rolled to a thickness of 111 m or less and then annealed into an endless shape to form a steel belt material, and then The steel belt material is characterized in that it is cold processed at a processing rate of 20 to 50%, and then subjected to aging treatment.

The steel belt material used in this invention is a material such as maraging steel or precipitation hardening stainless steel, whose properties can be significantly improved or improved by subsequent aging treatment. Use steel that has been rolled to a thickness of 1 inch or less and then annealed. Here, the reason why the thickness after rolling is 1 mm or less is to enable it to be applied as a band saw or a steel belt for a continuously variable transmission.

Next, the ends of the annealed rolled material described above are welded to form an endless steel belt material, and then the steel belt material is cold processed at a processing rate of 20 to 50%.

Here, the processing rate is set to 20% or more in order to sufficiently press the weld defective portion in the welded portion described above to eliminate the adverse effects of the weld defect. However, if the processing rate is too high, rolling becomes gradually difficult, so it was set at 50% or less.

Subsequently, after performing the above-mentioned cold working, an aging treatment is performed under optimal conditions depending on the material used, so that desired characteristics can be obtained.

(Example) Made of steel with chemical composition shown in M1 table, thickness 0.5m+
After rolling to a temperature of e, annealing was performed under conditions according to each composition.

Next, each of the above-mentioned annealed materials is welded into an endless shape to produce a steel belt material, and then each steel belt material is cold-rolled at a small processing rate shown in Table 2, and then the conditions according to each material are It was subjected to aging treatment.

Subsequently, the hardness and tensile strength of the base material and welded parts of each steel belt obtained through the above steps were measured, and the results shown in Table 2 were obtained.

/' As shown in Table 2, the same material No., L and positive, 2
Comparing the above, when the processing rate after welding is 10%, the hardness of the welded part is Hv490, and the tensile strength is 180.
kgf/+u2, whereas the processing rate after welding is 2
The hardness of the welded part in the case of 5% and 2 is HV590.
The tensile strength was significantly improved to 208 kgf/m+s2, a value close to that of the base material. Also, for positive 3 and positive 4 materials, the cold working rate after welding is 2.
By making it 0% or more, it was possible to make the hardness and tensile strength of the welded part close to those of the base metal part.

On the other hand, in the case of 5° cracking and 6, which uses non-aging material, even when the processing rate after welding is 20% or more, the hardness and tensile strength of the welded part after welding are Tatami (comparative example) A thin plate made of steel with the chemical composition shown in Table 1 and cold-rolled to a thickness of 0.5 mm at a processing rate of 40% was welded at both ends. After creating an endless steel belt material, an aging treatment was performed under conditions suitable for each material without cold working.

Subsequently, the hardness and tensile strength of the base material and welded parts of each steel belt obtained through the above steps were measured, and the results shown in Table 3 were obtained.

As shown in Table 3, in all cases, the hardness and tensile strength of the welded zone were significantly lower than those of the base metal.

(Experiment example) Next, the steel belts numbered 1 to 11 shown in Tables 2 and 3 were stretched across the boot 9 with a diameter of 100+ui, and while applying a tension force of 120 kgf/m+m2 to one pulley, As shown in Table 4, the material is maraging steel or precipitation hardening stainless steel, which can be age hardened, and the ends of the ribbon made from this material are welded to create an endless material. (No. 2) (No. 2) (No. 2)
It was confirmed that samples 4) to 4) had a considerably long rupture life and had excellent performance.

On the other hand, steel bell (No. 1), which had a low cold working rate after welding, had a short fracture life and the fracture location was at the weld.

On the other hand, for steel bells (Nos. 7 to 9) that were subjected to aging treatment without cold working after welding, the hardness and tensile strength of the welded part were considerably lower than that of the base metal, so
The fracture life was short and the fracture location was a weld.

In addition, steel healds using non-precipitation hardening materials (
No. 5.6, 10.11) had poor hardness and tensile strength in both the base metal part and the welded part, resulting in a significantly short rupture life.

(Effects of the Invention) As explained above, according to the method for manufacturing a steel belt according to the present invention, the thickness is 1 wr+1! ), then annealed maraging steel or precipitation hardening stainless steel is welded into an endless shape to make a steel belt material.
Since we applied I: at a processing rate of 50% and then subjected it to aging treatment, we were able to produce a steel belt with an extremely long life at break without any defects due to welding, despite the manufacturing process using welding means. Continuously variable transmissions are possible to obtain, and the cost can be significantly reduced compared to manufacturing endless steel healds by conventional spinning processing, and the demand for continuously variable transmissions is expected to increase in the future. It has very excellent effects and can be suitably used as a steel heald or mekuru saw.

Claims (1)

[Claims] (1) Maraging steel or precipitation hardening stainless steel that has been rolled to a thickness of 1 mm or less and then annealed is welded endlessly to make a steel belt material, and then the steel belt material is processed by 20 to 50% in the cold. Processed at a rate of
A method for producing a steel belt, which comprises then subjecting it to an aging treatment.